We normaly work on £100/day + a CC each. If you have specific meals etc. already planned, you can easily budget for these, e.g. you know what a character b/fast costs, so I often package this amount separately to keep it simple. Likewise if you're paying daily car park charges, you can identify how much you'll need for this. Alot depends as well on whether you will buy everything at the park (water @ $2-50/sml bottle), or buy a gallon at the supermarket & take your own in in a camelback or something. Likewise, will you carry snacks prebought, e.g bananas/crisps etc. or pay theme park prices? We employ both these tactics & the savings do mount up, but there again, that's just me!